The present invention relates to a system for conveying information recording media such as compact discs (CDs) and digital versatile discs (DVDs) into and out of an information recording/reproducing device.
The present application claims priority from Japanese Patent Application No. 2002-133893, the disclosure of which is incorporated herein by reference.
Information recording/reproducing devices such as digital audio systems designed for playing information recording media such as CDs or DVDs (hereinafter referred to generally as “discs”) are normally provided with a conveyor having an auto loading function, which loads a disc automatically into or out of the information recording/reproducing device.
It is essential for such conveyor to be able to load or unload a disc without failure which can be used for the information recording/reproducing device.
Basically, 12 cm diameter discs (“large discs”) DSC shown in FIG. 6A are standardized for CDs and DVDs, but there are also smaller, 8 cm diameter discs DSC′ as shown in FIG. 6B for CDs, which are also standardized.
There has also been developed a ring-shaped auxiliary component called an adaptor, which has a diameter of about 12 cm. As shown in FIG. 6C, an adaptor ADP′ has a coupling portion with a circular hole for coupling with a small disc DSC′. As shown in FIG. 6D, when attached to the disc, it forms a quasi-disc ADP which complies with the standard disc size of the large discs DSC.
An information recording/reproducing device for playing such a large disc DSC and a disc ADP with an adaptor which complies with the standard disc size must have a conveyor capable of identifying these discs DSC and ADP and loading/unloading them without failure, and of ejecting any foreign matter other than the acceptable discs. Such a conveyor, for example, has a configuration shown in FIG. 6E.
The information recording medium conveyor shown in FIG. 6E is provided with a conveying roller DRV for conveying a disc by rotational drive force, an optical sensor PD for detecting the track of the disc DSC or ADP passing along its center axis, a contact sensor MS for detecting the passage of the disc DSC or ADP by making a sliding contact with a circumferential portion of the disc, and a microprocessor (not shown) for controlling the rotation of the conveying roller DRV in accordance with the detection signals Sa and Sb output from the optical sensor PD and the contact sensor MS, respectively.
The optical sensor PD outputs the detection signal Sa of either a logic “H” or “L.” If it detects a disc face of a large disc DSC or a disc ADP with an adaptor, it outputs the logic “H,” whereas if it detects a portion other than the disc DSC or ADP or a portion of the clamping hole through which light passes, it outputs the logic “L.”
The contact sensor MS is spaced away from the optical sensor PD by a certain distance which is shorter than the radius of the large disc DSC or the disc ADP with an adaptor. It is supported on a spring SP or the like attached to a portion of the chassis of the information recording/reproducing device, so that it is resiliently biased towards the optical sensor PD. Therefore, when the disc DSC or ADP passes through against the biasing force of the spring SP, the contact sensor MS makes a sliding contact with the circumference of the disc DSC or ADP, thereby detecting the passage of the disc.
The contact sensor MS outputs a detection signal Sb, which is either a logic “L,” during it is in sliding contact with the circumference of the disc, or a logic “H,” when it makes no contact therewith.
When a large disc DSC or a disc ADP with an adaptor is inserted through an insertion hole (not shown), the optical sensor PD detects its distal end, whereupon, following an instruction from the microprocessor, the conveying roller DRV rotates in forward direction for loading the disc onto a tray TR arranged at a predetermined location behind the conveying roller DRV, where information recording/reproducing is carried out by an optical pickup system.
When unloading, the microprocessor instructs the conveying roller DRV to rotate in reverse direction, whereby the large disc DSC or a disc ADP with an adaptor which has been played and left in the tray TR is discharged from the insertion hole noted above.
FIG. 7A to FIG. 7F illustrate the changes in the position of the disc DSC or ADP being loaded onto the tray TR relative to the optical sensor PD and the contact sensor MS, and FIG. 7G is a diagram showing the changes of the detection signals Sa and Sb in time sequence t1 to t6.
FIG. 8A to FIG. 8F illustrate the changes in the position of the adaptor ADP′ relative to the optical sensor PD and the contact sensor MS, in an imaginary case in which the user has inserted only the adaptor ADP′ by mistake and this adaptor ADP′ is loaded onto the tray TR by the conveying roller DRV. FIG. 8G is a diagram showing the changes of the detection signals Sa and Sb.
FIG. 9A to FIG. 9D illustrate the changes in the position of the small disc DSC′ relative to the optical sensor PD and the contact sensor MS, in an imaginary case in which the user has inserted the small disc DSC′ by mistake and this disc DSC′ is loaded onto the tray TR by the conveying roller DRV. FIG. 9E is a diagram showing the changes of the detection signals Sa and Sb.
The microprocessor constantly monitors the changes of the detection signals Sa and Sb during the loading operation by the conveying roller DRV. If the microprocessor determines that the detection signals are changing in a predetermined, normal sequence shown in FIG. 7G, then it decides that a normal disc DSC or a disc ADP with an adaptor is being loaded in a normal procedure, and continues the loading of the same toward the tray TR.
However, if the detection signals Sa and Sb are changing differently from the normal sequence shown in FIG. 7G, e.g., if they are changing in the sequence shown in FIG. 8G or FIG. 9E, the microprocessor breaks off the loading operation and makes the conveying roller DRV reverse its rotating direction to forcibly discharge the small disc DSC′, adaptor ADP′, or whatever is inside, from the insertion hole, so as to prevent further troubles.
When unloading a large disc DSC or a disc ADP with an adaptor mounted on the tray TR, the microprocessor constantly monitors the detection signals Sa and Sb. If the signals are changing in the normal sequence which is the reverse sequence from t6 to t1 shown in FIG. 7G, the microprocessor decides that the unloading operation is being carried out successfully, and if not, it carries out an error recovery action such as reporting to the user the occurrence of an abnormality.
As described above, the conventional information recording medium conveyor is designed such that the microprocessor monitors the changes of detection signals Sa and Sb so as to ensure that loading or unloading is carried out appropriately. However, since there may be an unexpected situation brought about by the user's unpredicted action, the conveyor is desired to have a feature which can prevent troubles resulting from such unexpected situation.
For example, in the conventional conveyor, when an adaptor ADP′ alone is inserted by the user by mistake, the microprocessor detects an abnormality in the sequence of changes of the detection signals Sa and Sb during the loading operation by the conveying roller DRV, and causes the conveying roller DRV to rotate in reverse direction so as to forcibly eject the adaptor ADP′ from the insertion hole.
During this ejecting action by the driving roller DRV, supposing the user ignores this and carries out an unpredicted action, for example if he/she intends to forcibly pull out the adaptor ADP′ but stops pulling and leaves the adaptor, or, if he/she blocks the adaptor ADP′ being ejected, then the sensors may output detection signals Sa or Sb indicating that there is no adaptor ADP′ in the conveying path between the insertion hole and the tray TR, whereupon the micro processor decides that the adaptor ADP′ has been discharged, although it has actually not, and stops the ejecting operation, leaving the adaptor ADP′ in the conveying path.
More specifically, as a result of the unpredicted action by the user, the adaptor ADP′ may be stopped at a position where the optical sensor PD is located inside the adaptor's coupling portion, while the contact sensor MS is not in contact with the circumference of the adaptor ADP′, as shown in FIG. 10A. If this happens, the detection signals Sa and Sb will remain the same logic values as those between the time points t2 and t3 for a long period of time as shown in FIG. 10C. If the detection signals Sa and Sb remain the same logic values even after a predetermined timeout has elapsed, the microprocessor may decide that the adaptor ADP′ has already been discharged and stop the ejecting operation.
That is, because of the peculiar ring-like shape of the adaptor ADP′, the detection signals Sa and Sb are logics “L” and “H” both between the time points t2 and t3 and before t1 as shown in FIG. 10C, and they cannot be distinguished from each other. Therefore, if the detection signals Sa and Sb remain as logics “L” and “H” respectively for a long period of time, the microprocessor may decide that there is no object or adaptor ADP′ in the conveying path and terminates the ejecting operation.
FIG. 10B illustrates a situation similar to that shown in FIG. 10A, although with a different positional relationship between the adaptor ADP′ and sensors PD and MS. The adaptor ADP′ may be stopped as a result of the unpredicted action by the user at a position where the positional relationship is symmetric with that of FIG. 10A. In this case also, the microprocessor may stop the ejecting operation based on the determination that there is no object or adaptor ADP′ in the conveying path.
More specifically, if the adaptor ADP′ is positioned relative to the optical sensor PD and the contact sensor MS as shown in FIG. 10B, the detection signals Sa and Sb are the same logic values as those between the time points t4 and t5 in FIG. 10C, and because these cannot be distinguished from the logic values before the time point t1, the microprocessor will decide that there is no object or adaptor ADP′ in the conveying path.
Although such situations as described above are unlikely to arise, it is nevertheless necessary to take account of any possible actions made by the user, and to take measures for preventing troubles resulting therefrom by ensuring that loading and unloading are always performed appropriately.